For example XYZ enterprises t/over for AY 2012-13 Rs. 15 crores hence subject to audit u/s 44AB

But in AY 13-14, t/over reduced to Rs. 80 lacs so opted presumptive scheme of sec 44AD...

.in such a typical case CASS will pick the return for scrutiny....and then the regular assessment wil be completed by AO by gaining information from whatever records available with the asessee and the AO may also issue summons to parties connected in business dealings with the asessee and such other means...........But all in all it really become a challenge for AO to complete the assessment that to  with a target of raising a demand...